Step 1: Draw a plan of the aquaria with dimensions for the glazier to follow.

I've chosen a relatively simple inverted aquarium that sits in a shallow base aquarium as opposed to the "tunnel" that links 2 aquariums with a vacuum-filled "water-bridge".
I've enclosed drawings that you can either have a glazier construct or cut and you assemble.

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This is the final "draft" for publication.

It looks to me like you have reduced the surface area available to oxygen exchange. If this is the case the aquarium would probably support fewer fish optimally.

This was posted many, many moons ago!All current R&amp;D is shown on my YouTube channel.I have been drilling holes in the inverted aquariums along the waterline.The home-made vacuum pump is controlled by a re-cycled refrigeration microprocessor that runs the vacuum pump for 1 minute every hour.This draws air in from outside.When the vacuum stops the water level re-covers the inlet holes to maintain the level.<br>I was originally trying to keep the whole process simple so any one could try the idea.But, as refrigeration engineering and the application of vacuum pumps has been part of my work for the last 37 years the application of vacuum process's is second nature.Something like &quot;Nano aquariums&quot; where by the application of advanced filtration and sophisticated lighting a small aquarium can house a fair sized fish community.The mini truncated aquarium effectively doubles the water volume while occupying the same outside dimensions for the base.<br>If I can post a link to the video here it should be clear.<br><br>http://youtu.be/2SzIkVYieXc

I understand. The video made it much more clear. It does make for a very visually interesting aquarium. Its been many years since I have had my aquariums up and running. I hope one day to get at least one of them going again. My &quot;hacks&quot; of the systems were a great deal less ambitious. One simple one I tried that seemed to have success was placing an external filter on the side rather than the back. My reason for this was the idea that placed on the back the water flows into the tank where it soon collides with the front glass thus creating an unnatural (to the fish) turbulence. By placing the external filter at one end the water enters the tank and flows to the opposite side creating a current. I noticed soon after that many of the fish would position themselves in the most forceful part of the current. I assumed they benefitted in some manner from this.

this is incredible. i am so making one

If there are any points not clear, let me know.Many of the processes are detailed on "youTube", The Romaurie Effect.
Laurie

actually i read a little deeper into it and would prefer not to have to use a valve. so i decided to just make a smaller one and submerge it in a bucket or bathtub until it was full then pull it out so that it has a more natural vacuum effect. however, i really did like the concept and may consider doing this the correct way in the future.
also it would really help if you posted all the videos, or at-least the links here to this page.

There is another mehod to Vacuum" the water out.Actually I got the idea from Instructables from a guy who was looking after his parents house and had to remove water from a basement.He attatched a vacuum cleaner to a large drink dispenser bottle so the water is vacuumed into the bottle and not the "hoover".
What you do for the inverted aquarium is reduce the plastic tube diameter to about 3/8 inch, feed it to the top of the inverted aquarium and switch on.As the air is pulled out water flows in from the lower aquarium.When full, remove the tube and as long as the entrance to the inverted aquarium doesn't fall, the water stays in.A small submersible pump can be used to direct a water flow from the lower aquarium to the upper one.
The system I have detailed on youtube uses a vacuum pump controlled by a process timer to give a 2 minute vacuum every hour.This pulls air in thru 3 small holes just below thw waterline.As the water level climbs the upper tank, the holes are exposed to the air which is drawn in.
Elementary Bat Logic!

about how long does it take until you need to vacuum it out again

If there are no air leaks, the water level in the base aquarium does not fall below the entrance to the inverted aquarium, your pets don't drink too much water from the base aquarium, the vacuum remains constant.That means you will not have to vacuum again.
But, in practice one of the examples will cause a small drop of water.That's why I prefer having a "home-made" vac-pump at all times.
Just by browsing the responses to "Fishfreedom's" video clips you can tell the vast majority of people still can't grasp this concept.Even when I think I've given a perfectly full explanation of how this works, there's always one who will ask:"But what happens if the electricity fails?"
And as this site has a "be nice" comment policy it can really be frustrating at times.
As an aside, on one aquarium site, a guy very keen to buy one of these set-ups phoned Mr.Ho the builder of the "Bottomless" aquariums in Singapore.He was told he does not export but for information on how to build see "The Romaurie Effect".
You will notice in all his video clips the top is covered he gives no information how it is done.
I have the space and equipement to test various set-ups.I spent 18 months researching different methods to obtain this effect.
To date, a vacuum has to be produced to fill the inverted aquarium or tunnel.How you "make " the vacuum I have discussed at length on youtube.
The original idea for this came from a South African Doctor who made a perspex tunnel, filled it in a bath, closed the ends with threaded caps and then lifted it into place connecting 2 aquariums.He then unscrewed the caps and the water stayed in.
I immediately saw how by attatching a refrigeration "schreider" valve, I could do this on any size set-up.
There are some commecially available mini vacuum pumps.Not a lot of use for any "respectable" sized refrigeration or air conditioning application but bloody marvelous for inverted aquaria.
I don't half waffle on at times!

how do you change the water?

Syphoning the water out from the lower aquarium will also lower the water from the upper aquaium when the level drops below the entrance.When you have removed about 1/3 of the total capacity, start the vacuum pump and fill water into the lower aquarium.The water will be drawn back into the upper aquarium.
As my systemis outdoors with daily summer temeratures up to 46 Deg C. I lose about 4 liters of water from evaporation.I have a small refrigerator with chilled bottles of water to top up.Because of the process timer contorlling my vacuum pump, I just press a switch to activate the vac pump.

the same idea could be used to make a hero's fountain

See "Vacuum cleaner to wet vac" on Instructables for an alternate way to vacuum inverted aquaria.
I have just seen the smallest comercially available vacuum pump for refrigeration/air conditioning.Very compact, very nice construction.Too small for all but domestic refrigerators or car A/C but just the thing for pulling vacuums on inverted aquaria.
Cost about $95.